Refrigeration component

ABSTRACT

A SUCTION ACCUMULATOR IS PROVIDED FOR THE COMPRESSOR OF A REFRIGERATION SYSTEM WHICH INCLUDES A COMPRESSOR, AN EVAPORATOR AND A CONDENSER CONNECTED IN OPERATIVE RELATIONSHIP WITH REFRIGERANT EXPANSION MEANS BETWEEN THE CONDENSER AND EVAPORATOR. THE SUCTION ACCUMULATOR INCLUDES AN EVAPORATOR PRESSURE REGULATOR VALVE ON THE INLET WHICH IS A DEVICE SENSITIVE TO THE TEMPERATURE OF INCOMING EVAPORATOR GASES TO OPEN OR CLOSE IN ACCORDANCE THEREWITH   TO MAINTAIN THE PRESSURE-TEMPERATURE CONDITIONS OF THE EVAPORATOR AT A DESIRED LEVEL.

Dec. 14, 1971 w, B T M 3,626,715

REFRIGERATION. COMPONENT Filed Jan. 22, 1970 INVENTOR. PEI Bj/W/r/A/United States Patent O 3,626,715 REFRIGERATION COMPONENT Edward W.Bottum, 9357 Spencer Road, Brighton, Mich. 48116 Filed Jan. 22, 1970,Ser. No. 5,006 Int. Cl. F25b 43/00 US. Cl. 62217 3 Claims ABSTRACT OFTHE DISCLOSURE A suction accumulator is provided for the compressor of arefrigeration system which includes a compressor, an evaporator and acondenser connected in operative relationship with refrigerant expansionmeans between the condenser and evaporator. The suction accumulatorincludes an evaporator pressure regulator valve on the inlet which is adevice sensitive to the temperature of incoming evaporator gases to openor close in accordance therewith to maintain the pressure-temperatureconditions of the evaporator at a desired level.

BACKGROUND OF THE INVENTION Automotive air conditioning systems haveconventionally utilized expansion valves to provide expansion means forthe liquid refrigerant from the high pressure side of the system to thelow pressure side. In copending patent application Ser. No. 841,032,filed July 11, 1969, an air conditioning system which incorporates acapillary tube as the expansion device is disclosed. Either systempreferably employs the use of a suction accumulator between theevaporator and the compressor.

The present invention provides a suction accumulator which incorporatesan evaporator pressure regulator valve to control thepressure-temperature conditions of the evaporator to prevent evaporatorfreeze-up. Evaporator freeze-up is the condition when the evaporatorcoils are at a temperature low enough to freeze the moisture in the airpassing thereover with the result that the evaporator coils becomecoated with ice which acts as an insulator thus reducing theeffectiveness of the air conditioning system.

The evaporator pressure regulator valve is sensitive to temperature ofincoming evaporator gases which are directly related to the pressure inthe evaporator. When the temperature of incoming gases is too low, thevalve tends to shut off flow from the evaporator thus causing thepressure in the evaporator to increase with a resultant increase inevaporator temperature to thereby avoid freeze-up.

Incorporation of the valve in the accumulator results in a cost savingas a result of integration of the valve in the accumulator, as a resultof reduced installation costs and as a result of the less expensivevalve casing which does not have to be made of corrosion resistantmaterial such as copper, but may be made of steel because the valve issubjected only to contact with refrigerant gases. The accumulator isfurther advantageous in that any liquid resulting from actuation of thevalve will flow directly into the accumulator rather than into thecompressor of the system. The accumulator includes metering means formetering the flow of liquid to be compressor at a nonharmful rate.

SUMMARY OF THE INVENTION 3,626,715 Patented Dec. 14, 1971 let. A conduitwithin the casing extends from a point adjacent the bottom of the casingto the casing outlet. The conduit acts as a suction tube to draw liquidfrom the casing and expel it into the casing outlet at a metered rate..An evaporator pressure regulator valve is provided on the inlet. Thisvalve includes a valve element which is movable to open and closedpositions. A temperature sensitive valve element actuator is positionedon the upstream side of the valve element for subjection to the incominggases from the evaporator to move the valve element to the closedposition when the temperature of the incoming gases falls below apre-selected value and to move the valve element to the open positionwhen the temperature of the incoming gases rises to a pre-selectedvalue.

In the drawing:

FIG. 1 is an elevational view of a suction accumulator forming oneembodiment of the present invention with portions broken away for thepurpose of clarity;

FIG. 2 is a sectional view taken substantially along the line 22 of FIG.1 looking in the direction of the arrows; and

FIG. 3 is a side elevational view of another embodiment of a suctionaccumulator with portions broken away for the purpose of clarity.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The suction accumulatorsillustrated in the figures are adapted for use in connection with avehicle air conditioning system which comprises the usual compressor,evaporator and condenser connected together in operative 'relationship.Capillary tube refrigerant expansion means are provided between thecondenser and evaporator.

r Alternately, an expansion valve may be used between the condenser andevaporator. The suction accumulator is provided between the evaporatorand compressor to trap any liquid refrigerant emanating from theevaporator and to feed this liquid refrigerant to the compressor at ametered rate. Flow is accomplished by means of the suction created bythe compressor. The accumulator includes an evaporator pressureregulator valve which causes the evaporator pressure to remain at aminimum predetermined pressure which is selected so that thecorresponding temperature thereof will not permit the evaporator tofreeze. A vehicle air conditioning system of this type is disclosed inco-pending application, Ser. No. 841,032, filed July 11, 1969.

As illustrated in FIGS. 1 and 2, the suction accumulator 10 includes acasing 12 which comprises an openended tube 14 having an upper endclosure 16 and a lower end closure 18 secured thereto as by brazing.

An outlet tube 20 extends through the upper end closure 16. The outlettube 20 is U-shaped. One leg 22 of the tube 20 extends downwardly to apoint adjacent the lower end closure 1-8. The tube is then provided witha bend 24 and a second leg 26 extends upwardly and terminates in an openend 28 adjacent the upper end closure 16. A small metering opening 30 isprovided in the tube bend 24. Another opening 32 is provided in leg 22at the upper end to equalize pressure in both of the legs 22, 26. Aninlet tube 34 also extends through the upper end closure 16. The inlettube 34 extends for a short distance into the casing 12.

In operation of the accumulator cold refrigerant gas having a smallamount of entrained liquid refrigerant therein is received from thesystem evaporator and enters the accumulator through the inlet tube 34.An evaporator pressure regulator valve 38, to be later described,controls flow of refrigerant from the evaporator. The refrigerant gaseswhich enter the casing are drawn into the open 3 end 28 of the U-tube20, pass through both legs of the U-tube and exit via the leg 22. Thegases are passed from the U-tube 20 to the compressor of therefrigeration system (not shown). The compressor, which creates asuction, draws the gaseous refrigerant through the accumulator at arelatively rapid rate.

Liquid refrigerant which enters the accumulator through the inlet tube34 drops to the bottom of the accumulator and is subsequently drawnthrough the opening 30 and thence through the leg 22 and out of theaccumulator. It will be appreciated that the liquid which is meteredinto the leg 22 is entrained in the stream of gaseous refrigerant. Itremains entrained in the gas as it passes from the accumulator and isdrawn to the compressor of the system. The opening 30 acts as arestriction and causes liquid refrigerant to be metered into thecompressor at a controlled rate. The accumulator thus acts to preventlarge amounts of liquid refrigerant from suddenly entering thecompressor. Such sudden surges of liquid may result in eriously damagingthe compressor.

During operation of the refrigeration system in which the accumulator isinstalled, there are times when an unusual amount of refrigerant willcollect in the accumulator. For example, when the system is shut off,such as is the case with an intermittently-operated air conditioningsystem such as an automotive air conditioning system, the refrigeranttends to condense in the entire system and collect in the accumulator. Asimilar situation may occur when the system is operated under low loadconditions. The metering of the liquid refrigerant via the opening 30results in liquid refrigerant being delivered to the compressor at anon-harmful rate.

Referring now to the evaporator pressure regulator valve 38, it will benoted that this valve comprises an outer tubular casing 40 which is ofslighlty less diameter than the diameter of the inlet tube 34 and isreceived therein. The lower end of the inlet tube 34 has a spiderlikeconfiguration with peripherally spaced apart downwardly dependingmembers 42 which are secured at the lower ends thereof to a disc 44. Thespace between the members 42 permits flow of refrigerant from the valve38 into the interior of the accumulator casing. At the same time, thisstructure sreves to support the valve 38 at a position interiorly of theaccumulator casing. The upper end of the valve casing 40 extends intothe solid portion 46 of the inlet tube. The casing 40 may be sealinglysecured to the portion 46 as by brazing so that gases cannot escapearound the valve and into the casing 12. Alternately, if it is wished tomake the valve 38 easily removable, an O-ring may be used for sealingbetween the valve casing 40 and the inlet tube 34.

A slidable tubular valve element 48 is received within the casing 40.The valve element 48 is provided with spaced apart peripheral slots 50in the side walls thereof. Similar slots 52 are provided in the sidewallof the valve casing 40. When the slots 50, 52 are in registry, fluid maypass through the valve 38 into the casing 12. When the slots 50, 52 areout of registry, as illustrated in FIG. 1, the valve is closed to thepassage of refrigerant. The amount of refrigerant which will flow at anygiven time is determined by the degree of registry of the slots 50, 52.

A resilient bellows 54 is provided as the valve element actuator. Thebellows 54 is charged with a volatile substance, for example, arefrigerant that is the same as that used in the refrigeration system,normally Freon-l2 in a vehicle air conditioning system. The bellows 54functions according to the pressure-temperature relationship of theevaporator. Operation of the bellows, and thus the valve 38, is governedby the temperature of the refrigerant impinging upon the bellows. A risein evaporator temperature will increase the temperature of theevaporated gas passing from the outlet of the evaporator to the inlettube 34. The bellows 54 absorbs heat because of the fact that the chargein the bellows reacts in accordance with the pressure-temperaturerelationship, the pressure within the bellows decreases tending to movethe valve element 48 to a position where the slots are out of registerwith the slots 52 of the valve casing 40. The greater the evaporator gastemperature rise, the smaller the valve opens and vice-versa.

The evaporator pressure regulator valve 38, which partially orcompletely closes when the pressure in the evaporator begins todecrease, causes the evaporator pressure to remain at a minimumpredetermined pressure which is selected so that the correspondingtemperature thereof will not permit the evaporator to freeze. As abovementioned, Freon-12 is the refrigerant most often used in vehicle aidconditioning systems. This refrigerant will boil at 2l.7 F. below zeroat atmospheric pressure. In view of the fact that water freezes at 32F., the temperature in the evaporator must be controlled so that watercollecting on the core surface will not freeze and block air flowthrough the unit. In order to control the temperature, it is necessaryto control the pressure inside the evaporator. To obtain maximum coolingeffects, the refrigerant must remain in the evaporator long enough tocompletely vaporize. If insufficient refrigerant is present in theevaporator, cooling efficiency decreases. The evaporator pressureregulator valve is used to provide the necessary refrigerant pressurecontrol to aid in preventing evaporator freeze-up and to aid inmaintaining the efiiciency of the system.

A perforated strainer or screen 51 is provided in the casing 40 upstreamof the valve 38 to capture any foreign matter which may be entrained ingases entering the casing 12. The use of a strainer is preferred toprotect the working parts of the valve 38. Even small particles maycause valve failure by becoming entrapped between the valve casing 40and valve element 48 and preventing proper movement of the valve elementby the bellows 54.

FIG. 3 illustrates a modified suction accumulator 56. The accumulator 56includes a casing 58 which is normally oriented with the longitudinalaxis thereof in a vertical direction. The casing 58 comprises anopen-ended tube 60 having an upper end closure 62 and a lower endclosure 64 secured thereto as by brazing. A U-shaped outlet tube 66extends through the upper end closure 62. The tube 66 has aconfiguration and function like that of the outlet tube 20 described inconnection with FIG. 1 embodiment. A fusible plug 68 is provided in thelower end closure 64 as a safety device.

An inlet tube 70 extends through the sidewall of the tube 60. Theportion 72 of the inlet tube 70 exterior of the casing 58 encloses anevaporator pressure regulator valve 38 of the same type as described inconnection with the FIG. 1 embodiment. The inner end of the valve 38abuts against a spider-like stop structure 74 whereby gases emanatingfrom the valve 38 may pass into the casing 58. A peripheral flange 76maintains the inner end of the valve 38 in the position illustrated.

The portion 72 of the inlet tube 70 has an enlarged diameter so thatgases flowing from the slots in the valve 38 may exit into the portion72 of the inlet tube and thence into the accumulator casing 58. Theouter end 78 of the valve 38 is received in tube portion 80 of reduceddiameter. An O-ring 82 is provided on the end 78 of the valve tosealingly engage the tube portion 89 and prevent passage of gas aroundthe valve 38. Operation of the accumulator 56 is substantially the sameas operation of the accumulator 10 as previously described.

A bimetal element may alternately be used to bring the slots into or outof registry.

With both the accumulator 10 illustrated in FIG. 1, with the evaporatorpressure regulator valve 38 mounted internally of the accumulator inlet,and the accumulator 56 illustrated in FIGS. 3, with the valve mountedexternally of the suction accumulator casing, a cost saving is effected.Not only is the valve integrated with the accumulator construction thusreducing manufacturing cost, but also installation cost is reducedbecause of the need of installing only one basic element and the valvemay be constructed of, for example, steel, because the corrosion problemnormally associated with such valves is eliminated as a result of thevalve being subjected only to contact with refrigerant gases.Functionally, the accumulator structures illustrated are advantageous inthat any trickle of liquid which is caused by the back pressure exertedby the valve flows into the accumulator and is metered to the compressorby means of the accumulator structure rather than flowing directly tothe compressor without being metered, possibly resulting in damage tothe compressor.

What I claim as my invention is:

1. In a suction accumulator for the compressor of a refrigeration systemincluding a compressor, an evaporator and a condenser connected inoperative relationship, refrigerant expansion means between thecondenser and evaporator, said accumulator comprising a casing having aninlet conduit and an outlet, a conduit within the casing extending froma point adjacent the bottom of the casing outlet, said conduit acting asa suction tube to draw liquid from the casing and expel it into thecasing outlet at a metered rate, an evaporator pressure regulator valvelocated entirely within said inlet conduit, said valve including a valveelement movable to open and closed positions, and a temperaturesensitive valve element actuator positioned on the upstream side of thevalve element for subjection to the incoming gases from the evaporatorto move the valve element to the closed position when the temperature ofthe incoming gases falls below a preselected value and to move the valveelement to the open position when the temperature of the incoming gasesrises to a pre-selected value.

2. An accumulator as defined in claim 1, and further characterized inthat said inlet has a conduit portion extending exteriorly of theaccumulator casing, said valve being located in said exterior portion.

3. An accumulator as defined in claim 1, and further characterized inthat said inlet has a conduit portion extending interiorly of theaccumulator casing, said valve being positioned in said interiorportion.

References Cited UNITED STATES PATENTS 2,168,367 8/1939 Kucher 62-2173,012,414 12/1961 La Porte 62503 MEYER PERLIN, Primary Examiner US. Cl.X.R. 62-503

